Malodorous substances can be present in or on a variety of media or surfaces. Individuals can be highly aware of malodors on indoor surfaces and contained in indoor air, since there is generally limited air exchange and circulation in the indoor environment in comparison to the outdoor environment. Furthermore, olfactory detection of certain malodors in many indoor settings, such as residential homes, hotels, automobile interiors, hospitals, and office buildings may give rise to a perception that the indoor area is unsanitary or soiled. Other odors, such as those originating from certain foods, cooking activities, and burned tobacco products, while not generally thought of as unsanitary or dirty, can be regarded as unpleasant by many people. Thus, there exists a need for effective removal of malodors which reside on indoor surfaces or are contained within the indoor air space. This is particularly true for cigarette smoke malodor in the air or on fabrics such as furniture, window coverings and floor coverings.
Many products are sold which are designed to remove malodors from the indoor environment. For surface deodorization, this may be accomplished through the physical removal of a malodorous substance by cleaning (detersive) activities. Malodors present in indoor air can be removed using forced air fans combined with physical absorbents, or electrical devices which employ electrostatic deposition technologies. Reactive chemistries, such as oxidizing agents, which react with and transform a malodorous substance into one or more non-odorous substances can also be employed for malodor reduction/elimination applications.
Hydrogen peroxide, an inexpensive and somewhat reactive oxidant, has found application in the area of malodor elimination or reduction. However, such uses have generally been, among other things, complex systems, expensive compositions, and/or can stand improvement. For example, U.S. Pat. No. 4,036,994 discloses the use of aqueous hydrogen peroxide solutions to remove cooked food and smoke odors from the restaurant broiling grill emissions, in part through scrubbing of the grill exhaust gas stream with these solutions. The malodor elimination process described in this patent requires cooking foods over thin, high temperature ceramic briquets to enhance incineration of potential malodors, as well as scrubbing the grill exhaust gas stream with an aqueous hydrogen peroxide solution, followed by mixing the treated gas with ambient air prior to discharge to the atmosphere.
U.S. Pat. No. 4,550,010 discloses a process for deodorizing malodors in polluted air whereby the malodorous air is washed with an aqueous solution containing both hydrogen peroxide and ozone. Similarly, U.S. Pat. No. 5,904,901 discloses removal of odors from indoor environments using an apparatus which generates and discharges both ozone and an atomized hydrogen peroxide solution, whereby reaction between ozone and atomized hydrogen peroxide generates hydroxyl radical and is said to decompose various malodorous substances present in the indoor environment.
U.S. Pat. Nos. 5,071,622 and 5,137,687 disclose processes by which malodorous substances are removed from sewage treatment systems that emit odors. In the processes, odor abatement is obtained by contacting hydrophobic components of an odor-containing gas plume condensate with odor-trapping core particles containing precipitates resulting from reaction of ferrous ion, tannic acid, and hydrogen peroxide.
U.S. Pat. Nos. 6,365,099 B1 and 6,495,096 B1 disclose processes and systems by which malodorous reduced sulfur compounds are removed from liquid waste streams associated with sewage collection/treatment. The '096 patent describes a treatment process which utilizes aqueous deodorant compositions containing hydrogen peroxide and nitrate ion or hydrogen peroxide, nitrate ion, and a transition metal salt. The aqueous deodorant compositions of the '096 patent are mixed directly with the waste stream. The '099 patent describes a process and system by which sulfide odors are reduced or eliminated from the vapor spaces of waste handling and treatment systems by injecting a fine spray, mist or fog of an aqueous alkaline hydrogen peroxide solution into air spaces within sewage-containing system handling or treatment equipment such as sewage conduits, sewers, trunk lines, and other such structures.
U.S. Pat. No. 6,815,408 B2 discloses aqueous alkaline phosphate-containing hydrogen peroxide compositions for various odor elimination and disinfection uses. The aqueous compositions are introduced onto surfaces and into air handling ducts by the application of a spray or mist of the aqueous alkaline peroxide solutions. U.S. Pat. No. 6,815,408 B2 teaches criticality in the inclusion of alkaline phosphate agents in the aqueous liquid phase peroxide solutions both as a peroxide stabilizer and an oxidation accelerator/enhancer. U.S. Pat. No. 6,815,408 B2 teaches the deodorizing action as only associated with liquid phase alkaline solutions of hydrogen peroxide. Application of these compositions to malodorous surfaces is said to concentrate the alkaline peroxide in the aqueous phase, thus enhancing deodorization activity. The pH and non-volatile alkaline agents are central to the described invention. The teachings of U.S. Pat. No. 6,815,408 B2 do not extend to or infer reactions of hydrogen peroxide in the vapor state, as pH and non-volatile alkaline materials have no applicability to the vapor state.
WO 94/11091 discloses a catalytic process for removal of odors from industrial gas streams by scrubbing such gas streams through a fixed bed scrubber fitted with a solid packing bed containing a transition metal catalyst and a hydrogen peroxide-containing liquor.
Accordingly, there is a need for compositions and methods which are generally simple and inexpensive to manufacture and provide effective reduction or elimination of malodors, particularly cigarette smoke, from indoor air spaces and surfaces.